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Ultraviolet Exposure Box

Hello, this instructable goes through the construction of a simple stand alone Ultra-Violet exposure box.

Ever come across large and complex schematics or wanted to take advantage of ready PCB layouts included in tutorials and instructables? Well if yes, then this UV Box may help you solve that problem. I 've always liked developing my own circuits for any project, but as you take more advanced projects, more complicated circuitry with lots of more connections may be required. It may take effort and time to draw and etch a PCB, however the outcome is much more satisfactory!

A UV box is used to expose photo-resist boards in order to etch a printed circuit board for hobby electronics.

Please take note since it is not advised to expose or etch very detailed PCB's for it may fail to expose tiny gaps. This instructable explains every part of the UV Box, it includes schematics, code and used parts.

Attachments

Step 1: Find a Box

The first thing that must be done is to acquire a box. Dimensions are chosen by user, think of how big PCBs you want to etch and find/make a box depending on your needs.

It is advised to get a simple shaped box (not like the one used in this instructable), this will help with the positioning and modding of the box.

The inner space is divided into two parts. electronics and expose area. Since the design is on your hands you could place all electronics below the LED panel to get the most out of your space.

Think of where the glass will go and don't place it to close to the panel due to the led light angle (which is usually about 30 degrees).

In this box the approximate dimensions for the led part is about: 17cm x 14cm x 12cm(height) pay attention on height for you need to be sure the board will be evenly exposed from the panel.

Step 2: LED Panel

Lets start from the easy parts. Find lots of Ultraviolet leds (here used 80). Solder them in parallel and then add a resistor in series (anode or cathode doesn't matter).

Calculating resistor: Determine the voltage of the supply (Here 5 volts) and use Ohms law or online calculators. Or you could do it the old fashioned way.

R= (SupplyVolt. - LEDvolt) / (LEDcurrent * num of leds)

*The number of the leds you will use will mostly determine the ratings of your power supply for your project. In this project, power needs is about 3 Amps for everything. Warning: placed resistor must be capable of driving as much current as the led panel needs (in my case is 5 Watts).

Step 3: Power Supply

The most crucial part of the supply is the transformer, it must be able to provide lots of current.

Parts list:

Transformer: mains power to 12V 3Amps

LT1083CP linear regulator

Diode bridge rectifier (Capable of 3Amps)

280 ohm Resistor 1%

100 ohm Resistor 1%

10uF electrolytic Capacitor (2 pieces)

Double Slots Terminal Blocks (2 pieces)

The LT1083 is an adjustable linear regulator and uses 2 resistors (Voltage divider circuit) to determine the output voltage. They are about 3/1 to get an approximate of 5 volts output.

Schematic included in photos.

Step 4: Microcontroller

In order to make this project more automatic, a microcontroller board has been added. You could use an arduino instead.